Process oiv separating impalpable powder for paints



" G. W. GRISWOLD.

Making White Lead.

Patented July 18.11854- n. Puma PhoIo-Lllhcgrnphor. Washington. do

- UNITED srmrns PATENT OFFICE.

GEORGE W. GRISWOLD, OF CARBONDALE, PENNSYLVANIA.

PROCESS OF. SEPARATING .IMPALPAIBLE POWDER FOR. PAINTS.

Specification of Letters Patent No. 11,326, dated July 18, 1854.

Paint, &c., and that the following is a full,

carrying out said process, and in whichclear, and exact description of the same, reference being had to the accompanying drawings, which illustrate one of the plans of Figure 1 represents a side view of the apparatus and Fig. 2 a vertical, longitudinal section through the same.

Similar letters in both the figures denote like parts.

In making paint from mineral coal great diificulty is found in separating the impalpable powder, from the specula, and coarser material, and unless this is done effectually,

.the paint will have a grayish, instead of a black appearance.

The nature of my invention relates toa method of separating and depositing the impalpable from the palpable powder, and thus producing a durable and cheap black paint, the material being ground and reground until all is used.

To enable others skilled in the art to make and use my invention or process, I willproceed to describe, in connection with the drawings, an apparatus which has proved entirely successful. i A chamber is first inclosed in a tight metallic case A, and within this chamber is hung upon a shaft B, a square box or receptacle C, slightly inclined from front to rear as shown in the drawing. I have used this receptacle square because in revolving it more effectually carries up and drops the material to be separated; a round one with radial flanges will answer equally well. Above this chamber A, and communicating with it by the passages D D, are the receiving chambers E, E, provided with doors F F. The front end of the lower chamber is separated fro-m the main chamber by a partition G.

The coal from which the paint is to be made may be first roasted, or it may be used inits natural state. It is ground in a mill as fine as possible, and introduced into the apparatus through the spout. or hopper H, whichleads it through what I term the air chamber (I) into the rotating box C.

Heated or dry atmospheric air is introduced into the apparatus through :a pipe or tube J, and I have found in practice that air heated to about 110 Fahr. is the best for the purpose. In mid-summer with a perfectly dry atmosphere the process may be carried on without heat, but when humid, the heated air must be used. And I also find that, at times the heated air becomes sluggish and does not carry up the powder with regularity, either fromreacting currents or a partial vacuum in the chamber A. To remedy this, I use a fan K, which may be rotated by a belt in any well known man ner, and when this fan is necessary or to be used, a door L, opposite to it, is to be opened, to admit the blast, which must be very gentle into, and through the chamber I, to the chamber A, and thence through the passage D, and first receiving or depositing chamber E, and then through the passage D, and second receiving and depositing chamber E, and thence passes out through the screen or cloth covered opening M on top. I have only represented two chambers for receiving the impalpable powder thus carried up, but any convenient number may be used.

In order that aregular current of heated air may be used, a thermometer may be attached to the air chamber I, and although as stated a less temperature may at times be used, yet about 110 of heat will produce the proper current for carrying up, and allowing the material tosettle or deposit. I

have also by this means very successfully separated, sand, emery and ground glass, into various degrees of fineness, for making what is termed sand paper.

Having thus fully described the nature of my invention and shown how the same may be reduced to practice, what I claim therein as new and .desire to secure by Letters Patent, is

The process of separating and collecting impalpable, from coarser substances, such as ground coal for the purposes of paint, or other mineral substances, by means substantially such, as herein described and represented. I

G. W. GRISWOLD. 

